Method for forming steel strip into loose coil



g- 3 1966 NOBUO URUSHIYAMA ETAL 33 METHOD FOR FORMING STEEL STRIP INTOLOOSE COIL Filed Sept. 11, 1964 FIG! INVENTORS Nobuo Urushiyama TefsuoMofomura Hiram/chi Koshiishi 5 wwawfzz, J54)! 1? WM United States Patent3,268,998 METHUD FOR FORMING STEEL STRIP INTO LOOSE @OIL NohuoUrushiyama, Tetsno Motornura, and Hiromichi Koshiishi, all of KitakyushuCity, Japan, assignors to Yawata Iron dz Steel (10., Ltd, Tokyo, JapanFiled Sept. 11, 1964, Ser. No. 395,771 Claims priority, applicationJapan, Sept. 16, 1963,

lift/49,720 8 Claims. (Cl. 29-423) This invention relates to a methodfor forming steel strip or band steel (herein-after called strip) intoloose coil.

It has been wide practice to subject steel strip to heat treatment forvarious purposes. The strip to be heattreated is, in most cases, coiledand then put in a heat treatment furnace. In order to make the wholesurfaces of the steel plate come into uniform contact with the annealinggas or the gas inside the heat treatment furnace, it is necessary tocoilthe strip so that each lap of the coil may not be in closed contactwith the inner and outer laps. For this purpose, the strip to undergoheat treatment is shaped into loose coil so that any adjacent laps ofthe coil may not be in close contact with each other. To form such aloose coil, it is commonly practiced to erect a tight coil and to use aspecial loose-coil shaping apparatus for winding wire, nylon rope, orthe like in the coil on one side. However, the wire, nylon rope, or thelike thus Wound in the coil is usually pulled out prior to heattreatment, or, in case the wound material does not burn, the coil isheat-treated with the spacer, and then, at the time of recoiling, thespacer is removed.

Accordingly, the coil thus formed must be handled with care so that thelaps do not shift and also strict care must be taken of the coil to staycylindrical during keeping and not to warp out of shape. Moreover, inthe formation of a loose coil as mentioned above, the necessity of aspecial complicated device and other various inconveniences areinevitable.

An object of this invention is to eliminate the abovementioned defect,and aims to facilitate extremely the formation of strip into loose coilby winding bands of an inflammable material, such as paper tapes,between the laps of the coil of strip simultaneously with the coilingprocess, and then heating the coil in an oxidising atmosphere to burnaway the bands of the inflammable material wound between the laps of thecoil of strip.

Another object of this invention is to provide a process for easyformation of strip into loose coil by utilizing the usually used take-upmotion and the like as they are, without the conventional specialloose-coil shaping apparatus.

A further object of this invention is to provide a loose coil of stripwhich can be handled as easily as an ordinary tight coil with nonecessity of any such special care as needed in the handling of theprior loose coil.

The other objects and characters of the present invention will be fullyunderstood by reference to the appended claims and the followingdescription taken in connection with the accompanying drawing, whichshows exemplary embodiments of this invention.

FIG. 1 is a side view showing the formation of a loose coil of thisinvention by means of up coilers.

FIG. 2 is the plane view showing the same formation as FIG. 1.

FIG. 3 is a side view that illustrates the loose-coil formation of thepresent invention by the use of a tension reel.

This invention will be detailed hereunder. According to the presentinvention, a loose coil can be coiled by 3,253,998 Patented August 30,1966 an ordinary coiler and that with the coil axis in the horizontaldirection. However, the coil axis may be in the vertical direction as atthe time of the conventional formation of a loose coil, or may beinclined. The possibility of setting the coil axis in the horizontaldirection in the loose-coil formation of the present invention givesrise to such advantages as to facilitate the formation of strip intoloose coil which has so far been regarded as diffi-cult and further toallow the coil effective heat treatment.

Besides, the loose-coil forming process of this invention may employeither of the shaft-winding system which utilizes a tension reel or thelike and the up coiler system which makes use of bending rollers, thus,in effect, being applicable to any type of apparatus that is capable ofcoiling strip.

This invention contemplates to coil strip together with inflammabletapes of paper or another materialso that a loose coil may be formed.The tapes are wound between the laps of the coil of strip at the sametime with the coiling, and the inflammable matter should be such amaterial as paper or another plant fiber which may be burnt up withoutproducing any, especially sticky, residue. This is because the stickingof the remainder to the strip after the combustion of the matterinterposed in the loose coil of strip shaped in accordance with thepresent invention may cause troubles in the subsequent treatingprocesses, such as contamination of the cleaning solution in the washingprocess. In case, however, the residue after the burning of the spacersis not sticky, or easily falls off, or can be removed by means of asimple wiper or the like, the material of the tapes need :not bestrictly limited to plant fiber but may be another substance, though itis most desirable that the burning; of the spacer does not give rise toany remainder.

The positions where the spacers are placed during the laps according tothis invention are most preferably the trimming parts on both sides ofthe strip; however, spacing at other positions is also possible. In sucha case as stated below, however, it is advisable to avoid, to the mostpossible extent, the spacing at positions except the trimming parts,namely, in case the main part of the steel plate should be free from thestrain due to the spacers, it is necessary to wind the spacer along thetrimming parts on both sides of the strip.

Besides, in case, as mentioned above, the main body of the steel plateshould be free from the strain due to the spacer, the spacer may also beas wide as the strip all along the strip. In this case, however, a greatquantity of gas evolves at the time of the combustion of the spacer,requiring much trouble in the adjustment of the atmosphere gas in theheat treatment process following the burning process; further, this isparticularly undesirable in the case of a steel that is subject toinfluence of carbon.

As to the shape of the spacer in an embodiment of the present invention,the shape of tape may always stabilize the matter at the spacingposition; while, in the case of a twisted material such as paper string,the spacing position is apt to shift, requiring much care of winding itbetween the laps. However, two or more twisted cords arranged inparallel with each other so as to be one body are good in stability.Besides, the thickness or number of the spacers governs the clearancebetween the laps of the loose coil of strip; however, in View of theintended looseness, the thickness of more than 0.8 millimeter may beexpected to bring about a good result.

Next, two exemplary embodiments of this invention will be explained inconnection with the accompanying drawing.

FIGS. 1 and 2 are side view and a plan showing the application of theprocess for the loose-coil formation of this invention to up coilers. Inboth figures, strip S is guided by a couple of rolls 6 and 6 and anothercouple of rolls 5 and 5' into a bend device composed of bend rolls 2, 3and 4, by which the strip S is bent so as to meet the desired coildiameter, and then sent to up coilers 1 and 1'. On the other hand, coilspacer A is guided by rolls 6 and 6 so as to be positioned in thetrimming parts of both sides of the strip, and, through the bend device,led to the up coilers together with the strip. In this embodiment, papertapes having a thickness of 0.13 to 26 millimeters are employed as thespacer A and steel strip having a thickness of 0.5 to 3 millimeters areemployed as the strip S. Our tests showed best results in case of thetapes having a thickness of 1 millimeter. FIG. 3 shows another exemplaryembodiment of this invention by the shaft-winding system. Strip S iswound around a winding reel 7 simultaneously with the same paper tapes Aas used in the embodiment of FIG. 1. In the case of the employment ofthe shaft- Winding system for embodying this invention, the windingapparatus may be set up by the simple utilization of a Winding reel.

When the loose coil thus formed was heated and the paper tape-s asspacer were burnt, the coil was found to become a perfect loose coil andno ash was attached to the strip. The gas produced during the combustionof the paper tapes is suctioned, and the atmosphere gas in the burningprocess is completely driven away after the burning, for providing anatmosphere necessary for the heat treatment process.

As apparent from the foregoing description, the present invention hassuch advantage as to permit a loose coil to be formed surely and by anordinary winding method by utilizing an extremely simple apparatus suchas a winding reel.

What we claim is:

1. A method of heat treating a strip of steel, comprising the steps ofplacing a flammable material on the strip, rolling said strip of steelinto a coil with the flammable material between the spires of the coiland spacing the spires of the coil, heating said coil to burn away theflammable material completely so as to leave a space between the spiresof the coil, removing the gas produced by the burning of the flammablematerial from between the spires of the coil, and subjecting the coil toa heat treatment .in a heat treatment gaseous atmosphere.

2. A method as claimed in claim 1 in which said strip of steel and theflammable material are coiled about a horizontal axis.

3. A method as claimed in claim 1 in which the step of burning theflammable matenial comprises heating the coil with the flammablematerial between the spires thereof in an oxidizing atmosphere.

4. A method as claimed in claim 1 in which the flammable material is amaterial which leaves no residue on the surfaces of the strip of steelwhen it has burned.

5. A method as claimed in claim 1 in which the flammable material is intwo lengths, one lying along the strip of steel adjacent one edge andthe other lying along the strip of steel adjacent the other edge, saidlengths being substantially parallel with each other.

6. A method of heat treating a strip of steel, comprising the steps ofplacing a flammable material on the strip, rolling said strip into acoil with the flammable material between the spires of the coil andspacing the spires of the coil, placing the coil in an annealing furnacewith the axis of the coil in a vertical direction, supplying heat to theannealing furnace to burn away the flammable material completely andletting the residue fall from between the spires of the coil so that aloose coil having a space between the spires thereof remains, removingthe gaseous products of combustion from the annealing furnace, andannealing the coil in the annealing furnace.

7. A method of coiling a strip of steel, comprising the steps of placinga flammable material on the strip, rolling the strip into a coil withthe flammable material between the spires of the coil and spacing thespires of the coil, and heating the coil and burning the flammablematerial completely out from between the spires of the coil.

8. A method of coiling strip steel as claimed in claim 7 in which theflammable material is in two lengths, one lying along the strip of steeladjacent one edge and the other lying along the strip adjacent the otheredge, said lengths being substantially parallel with each other.

References Cited by the Examiner UNITED STATES PATENTS 1,296,934 3/1919Drouilly 29423 X 1,994,767 3/1935 Heintz 29423 2,075,815 4/1937 Knox29173 2,386,823 10/1945 Thornburgh 29400 2,932,884 4/1960 Lyon 29423JOHN F. CAMPBELL, Primary Examiner.

THOMAS H. EAGER, Examiner.

1. A METHOD OF HEAT TREATING A STRIP OF STEEL, COMPRISING THE STEPS OFPLACING A FLAMMABLE MATERIAL ON THE STRIP, ROLLING SAID STRIP OF STEELINTO A COIL WITH THE FLAMMABLE MATERIAL BETWEEN THE SPIRES OF THE COILAND SPACING THE SPIRES OF THE COIL, HEATING SAID COIL TO BURN AWAY THEFLAMMABLE MATERIAL COMPLETELY SO AS TO LEAVE A SPACE BETWEEN THE SPIRESOF THE COIL, REMOVING THE GAS PRODUCED BY THE BURNING OF THE FLAMMABLEMATERIAL FROM BETWEEN THE SPIRES OF THE COIL AND SUBJECTING THE COIL TOA HEAT TREATMENT IN A HEAT TREATMENT GASEOUS ATMOSPHERE.